1. Field of the Invention
The present invention generally relates to an X-ray irradiation apparatus provided with an irradiation range monitor.
2. Description of the Prior Art
A conventional X-ray irradiation apparatus provided with an irradiation range monitor has been disclosed in, for example, Japanese Pat. Laid-Open No. Sho 58-133239. This apparatus, as shown in FIG. 7 herein, comprises an X-ray transmitting mirror 3, which transmits an X-ray a but does not transmit a visible ray b, such as a laser beam. The mirror 3 is provided with a reflecting surface 3A disposed on a downstream side in an X-ray irradiating direction and installed between an X-ray irradiation device 1 and an object 2 to be subjected to the application of X-rays so as to be inclined relative to an axis P of an applied X-ray. A visible light projector 4 is installed so that the visible ray b may be applied to an X-ray transmitting position Q of the reflecting surface 3A, and an axis P.sub.1 of a reflected light of the visible ray b may be coaxial or nearly coaxial with the axis P of an applied X-ray. In addition, referring to FIG. 7, reference numeral 5 designates a collimator for converging the X-ray a and the visible ray b so that they may be parallel. Reference numeral 6 designates an X-ray fluorescence analyzer for detecting a fluorescent X-ray c emitted from the object 2 to be subjected to the application of X-rays, and reference numeral 7 designates visible ray projection range-detecting means.
However, with the X-ray irradiation apparatus having the above-described construction, a diameter of the X-ray irradiation range amounts to about 1 mm. In addition, in order to make the diameter of the X-ray irradiation range down to, for example, several ten microns, it is necessary to reduce an inside diameter of the collimator 5 and increase a length of the collimator 5, but it is remarkably difficult to obtain such a construction. Besides, even though such a construction may be achieved, it is difficult to obtain the X-ray irradiation range having the desired diameter, that is, to sufficiently converge the visible ray b which is a guide light. Moreover, it is difficult to monitor a position where the X-ray having a small-sized irradiation range is applied, or a range thereof on the object 2 to be subjected to the application of an X-ray. Accordingly, such monitoring has been hardly conducted with high accuracy when, for example, the object 2 to be subjected to the application of an X-ray is inclined.